Lightning And Hail Thunderstorms example essay topic

Formation of Thunderstorms, Lightning, Hail and Blizzards Thunderstorms Thunderstorms are formed when temperature imbalances are present in the atmosphere. They are a violent example of convection. The warming of the air near the earth and / or the cooling of the air above puts the warmer lighter layers below the colder denser layers. This causes instability and convection overturns the layers. The colder, denser air sinks below the warmer lighter air which is rising rapidly. The same conditions may occur when warm buoyant air is forced up by a wedge of cold air undercutting the warm air mass or an air mass is forced to rise over a mountain.

In the first stage of thunderstorm development and up draft carries warm air past its dew point. The water vapour held by that air mass condenses into water droplets or ice if the dew point is below zero. The continued upward movement of the air mass makes very large clouds like mounds, domes and towers (cumulous clouds). Winds above may boost updraft or convection Continued condensation releases large amounts of latent heat which is the primary source of energy. Once a cloud starts to form it is the release of latent heat which keeps it growing.

Particles grow by colliding, combining which increases their size forming rain and snow. When droplets are heavy enough to fall against the updraft, precipitation occurs. This causes a down draft. The velocity of the down draft is further increased by evaporation al cooling and frictional drag (rain and snow drags sown the surrounding colder air, which increases the velocity of the drag).

The cumulous cloud increases in size, height and width which results in a cumulonimbus cloud which sometimes extends vertically over 16 km. This is the second or mature stage of thunderstorm formation. The last stage in the formation of a thunderstorm is dissipation. The strength of the updraft within the thunderstorm is reduced and the strength of the downdraft remains. Thunderstorms mainly disperse when there is no longer any lifting agent which can continue to fuel the updraft.

There are four main types of thunderstorms, single cell, multicell clusters, multicell lines or squall lines and supercells. The difference between the types of thunderstorms is not to do with the formation but the amount of cells in the thunderstorm and how they are positioned. A single cell has one cell; multicell cluster has many cells bunch together; multicell lines have cells in a line like formation and supercells which are small well organised thunderstorm where the down draft and updrafts do not interfere with each other and updraft rotates (meso cyclone). Lightning Lightning is a result of thunderstorms and sometimes dust devils and blizzards. Lightning is an electrical discharge resulting from a build up of positive and negative charges within the thunderstorm cloud.

Basically the top of a thunderstorm has a positive charge and the bottom has a negative charge. The bottom also has a small layer of positive charge which is carried up by updrafts. Sheet lightning is when lightning moves within a cloud (intra-cloud lightning discharge) and also when the negative charge moves via the positive base to strike the earth which has a positive charge (cloud-ground flash). Lightning will also move from ground to cloud, cloud to cloud and in many other ways. Hail Hail is formed when water droplets falling from the upper regions of a thunderstorm are caught by the rising updraft and carried to below 0^0 C and the droplet freezes. As it falls again it melts slightly and picks up further layers of water.

It may get picked up by the updraft again and by carried to below 0^0 and freeze it again. This may happen over and over, letting the hail gather more and more layers until it becomes too heavy to be carried up by the updraft and falls to the ground. Blizzards Blizzards are winter storms that can be very dangerous. They are a combination of blowing snow and wind which results in little or no visibility. Heavy snow and brutal cold often go with blizzards they are not necessary. Strong winds will often pick up snow, creating ground blizzards.

A blizzard is defined as a storm which contains large amounts of snow or blowing snow. Blizzards often occur to the northwest side of a powerful thunderstorm. The difference in low and high pressure between the two locations results in extremely strong winds. These winds pick up snow on the ground or blow snow that is already falling. Effects of Thunderstorm, Lightning, Hail and Blizzards Thunderstorms, Lightning and Hail Thunderstorms are dangerous for many reasons, but the most common effects of a thunderstorm causing damage, injury and death are: lightning, hail, flash floods, strong winds and tornadoes.

Lightning is a bigger killer than tornadoes taking more lives than tornadoes each year. Lightning is also responsible for many fires. Thunderstorms are able to turn a peaceful water way into a raging torrent of water. These can break there banks flooding whole town if the downpour doesn't ease up. Hail can become deadly during a thunderstorm as it can fall to earth at speeds of 160 km / ph. It usually takes extreme storm to create hail big enough to do damage, but hail the size of hens egg will dent a car and hail the size of a baseball will kill if there is nothing to slow down its fall to earth.

An example of where hail and flash floods have caused extreme cases of damage is in Texas 1995 where the two combined caused two billion dollars worth of damage. On a whole hail causes approximately one billion dollars worth of damage to crops annually plus the numerous dollars of personal property damage. Sever winds are a real problem. Winds of great strength can damage roofs, chimneys, break tree limbs, topple small trees and destroy street signs, then turning these in to missiles.

Down bursts (strong winds produced by downdrafts) have often been mistaken for tornadoes because the extent of the damage is severe. Structures on the ground and planes in the air are in real danger. The most severe effect of a thunderstorm is the tornadoes that can be produced from supercells thunderstorms. They are produced near the spiraling updrafts. Blizzards Blizzards can produce numerous dangers. Cars can crash because of the snow slick roads, buildings can collapse under the weight of the snow piling up.

People can be trapped within homes or automobiles without utilities or other services. Water may freeze pipe and cause damage after thawing. People can get frostbite and hypothermia, the later sometimes killing. Flooding may result as the snow melts, blocking roads. Often fire is a real killer, people do silly things such as leaving kitchen appliances on and a fire results. The real problem is that often the water supply for the firemen is frozen so it is a struggle to put out the fire.

How Do Thunderstorms Affect Australia Thunderstorms occur in every part of Australia but vary in frequency from many in the north to few in the south east. They are more common in the warmer months especially in the north. In the summer a combination of heat convection, the lowering air pressure and the rising moisture levels generate large areas of thunderstorms in the north. In the south thunderstorms are more often in winter where the cold air masses flow over the relatively warm ocean causing brief storms that may or may not result in hail. The most severe storms in Australia occur along the western slopes of the Great Dividing Range and the east coast from NSW to Queensland. Some of these storms have given birth to tornadoes.

The most common cause of damage associated with thunderstorms in Australia is downburst. Some severe storms cause up to three million dollars worth of damage. The effects on Australia are generally the same as the effects world wide, general destruction of property and crops. Survival Techniques for Thunderstorms Before the storm comes: Secure doors, windows and loose objects outside. Bring all animals in or place them in a covered secure area. Stay in side or if you are in a car park under some form of cover, but not trees as the branches or tree may fall.

Indoors during storm: keep updated on the storm, don't use electrical appliances as lightning may be transmitted and avoid using water from taps. Lightning: your car is safer than outside in the storm as it acts like a hollow metal conductor, meaning the charge doesn't fill the interior, just be careful of the fuel tank. Victims DO NOT carry an electrical charge and need to be helped immediately Outside during storm: get into a building or covered area as soon as possible. If the storm develops a tornado it is better to be somewhere other than a car. Keep away from bodies of water and anything that could potentially act as a lightning rod.

Never shelter under a single tall tree as this will increase your chances of being struck. If you are in a boat on the water, head to the shore as quickly as you can. If you are outside and there isn't anywhere to shelter, squat low with you hands gripping your knees but don't lay down as this increases your contact with the ground. If you feel your hair stand on end drop anything metal and squat down as lightning is about to strike. Also be careful in low lying areas as flash flooding may occur library. thinkquest. org/12151/thunder. html web web weather. cool. edu / sirvatka /ts. html web web web web web lightning storm. com web web web web web home. imprimis. com. au / oz thunder / thunder. htm web web web members. aol. com / wind gust / BlizzadsandNoreasters. html web.